My vegetable garden was a disappointment; how can I fix the soil?

Q: I had terrible luck with multiple seeds/starts in my garden beds this year. I think it is my soil but I’m not sure what to do about it.

The soil is two to three years old, a mix from a bulk company. I admit I do not think I have added compost to them ever. In a panic, I top dressed and even mixed in some bagged compost late in the season (June, I think).

The only plants that have really done well are my tomatoes (top dressed with compost) and sweet peas (no tilling, composting, anything). There is one bed with new soil and the sunflowers took off wonderfully. In another bed with the older soil, a different kind of sunflower that was planted from seed the same day is doing terribly, despite having mixed compost in late in the season.

Other things I have had fail in the old soil beds: zucchini seeds (1 to 2 years old), kale seeds (new), kale starts (from a friend), cucumber starts, carrot seeds (packed for 2020), radish seeds (packed for 2020), dill starts, cilantro starts. I even have some new herb starts that are growing more slowly than I would have expected (sage, lavender, rosemary, thyme), though they are growing.

I did try using bagged fertilizer for starts in multiple beds according to the directions. It did not seem to make a difference. There is a large sequoia in the neighbor’s yard. I wonder if the needles from this tree are playing a role.

Should I get my soil tested? Amend more? I have never had such poor outcomes. I planted different things in these beds than have been planted in the past one to two years.

A: It’s frustrating to work so hard to get vegetables to grow and get disappointing results. Having a soil analysis done would give you especially useful information, particularly if you test the new soil separately from the old soil, so you can compare them. The analysis will tell you how much organic matter is in each sample, the pH, quantities of the nutrients nitrogen, phosphorus and potassium, and other properties of your soil. If you elect to pay an additional couple of dollars, they will recommend how to fix problems in your soil. A soil analysis is not expensive, and could even save you money by letting you know exactly what your soil needs. There are several labs that do soil analyses, including A&L Labs that has offices in the Portland area.

Improving our soil is an ongoing, important part of our work as gardeners. It means that our gardens improve every year. And it doesn’t take much.

One addition to your raised beds that will really help improve your soil is organic mulch. Just 2 to 4 inches of organic mulch covers the soil, slowing surface evaporation and keeping the soil moist and the roots cooler. Mulch blocks the light, slowing the development of weeds so they don’t compete with your vegetables. Finally, mulch, as it breaks down, adds organic matter to your soil. This article has good information on Improving Soil with Organic Matter.

For now, spread 2 to 4 inches of loose, organic mulch (woodchips, bark or compost) under your plants. Keep them well watered — about 1.5 inches of water once a week, or more during hot periods. Give them a boost of a slow-release organic fertilizer. They may still surprise you.

Anne Schmidt, Oregon State University Extension master gardener

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